This strategy requires the identification and reduction or elimination of unnecessary workplace noise. The task can be accomplished by modifying employees’ noise-producing behaviors and by replacing office noise-generating equipment with quieter technologies.

Despite its exclusion from the ABC Rule, workplace noise source reduction has been one of the defining influences for developing acoustic control in modern offices. Building mechanicals such as heating, ventilating and air-conditioning equipment have become progressively more silent. Office equipment has followed the same path, progressing from typewriters and noisy copy machines to early printers and finally, to modern keyboards, laser printers and photocopiers. However, some new technologies such as speakerphones can actually increase workplace noise levels, and their use should be carefully considered.

Changing behaviours can also significantly reduce the level of office noise. Reasonable office etiquette should be enforced, but it must be recognized that some workplace noise is unavoidably created while employees perform their tasks. One of the goals of good acoustic control is to provide employees with a comfortable working environment that lets them perform their tasks without feeling as though they are disrupting or irritating others.

Reducing office noise at the source has practical limitations. Once this method has been exhausted, any remaining workplace noise is there by necessity or because it is infeasible to eliminate. These noise problems must be controlled in other ways.